[FEAT] Opt-out of graphql-scalars (generally, or per scalar)

[feychenie]

Note: maybe this is already supported (or there is a reasonable workaround) and I did not find how to do it, then it would be amazing and just a docs improvement.

Is your feature request related to a problem? Please describe. I would like to be able to use my own scalar definition for a scalar that already exists in graphql-scalars. As an example, Currency provided by the library allows all existing currencies, but I would like to build my own version that would represent only the subset of currencies supported by my platform.

Describe the solution you'd like Possible solutions for opting out, in my perceived order of complexity (any of these would work for me):

• a simple 'opt-out from graphql-scalars' global config on the preset. All-in or all-out.
• or a granular version of this config to pick the scalars you want to opt-out for
• or if a resolver file for a scalar is present, use it instead of the one from graphql-scalars and use the codegen standard scalars config for the TS type.

Describe alternatives you've considered I considered using a different name like CurrencyCode, but then had the same requirement for other scalars, and trying to find more and more alternative names eventually ended up with ridiculous scalar names. Good naming is too important.

[eddeee888]

Hi @feychenie! This is currently partially supported but I like your suggestions 👍

By chance, I've recently started working on https://github.com/eddeee888/graphql-code-generator-plugins/pull/117 which makes the integration with graphql-scalars a bit more flexible.

Once it's done, we can use it for your first suggestion.

We can opt-out by setting scalars config to false. Note that scalar resolver files are still created in corresponding schema folder, so it is possible to import/implement your own

// codegen.ts
//...
generates: {
 "src/schema": defineConfig({ scalarsModule: false }) // default is `scalarsModule="graphql-scalars"`
}

I'll follow up with more granular cases soon

[eddeee888]

For your second suggestion ( override certain scalar but keep the rest from graphql-scalars ), you should be able to do it now with this (slightly verbose) config:

Let's say you have these scalars (which also exist in graphql-scalars):

# schema.graphql
scalar DateTime 
scalar Currency # Say we want to override this

Then , we can use externalResolvers to manually choose a custon resolver implementation. Optionally, we can use typesPluginsConfig.scalars to override graphql-scalars 's codegen type.

// codegen.ts
// ...
generates: {
  'src/schema':
    defineConfig({
      externalResolvers: {
        Currency: 'your-module/CustomCurrencyResolver#default as CustomCurrencyResolver', // set this to use own implementation
      },
      typesPluginsConfig: {
        scalars: {
          Currency: 'string', // set this to override graphql-scalars' default codegen type
        },
      },
    }),
},

---

There will be one option to override Scalar in the future, rather than having to do it in two places :)

[eddeee888]

Hi @feychenie ,

Better Scalars options will be available in v0.5: https://github.com/eddeee888/graphql-code-generator-plugins/pull/130

You can have a preview by installing the alpha version:

yarn add -DE @eddeee888/gcg-typescript-resolver-files@pr130-run207-1

Here's a codebase with the alpha version wired up: https://github.com/eddeee888/poc-gcg-server-preset-0-5-0/pull/1

---

Here's a quick explanation of the options:

• scalarsModules: can be set to false to opt-out of using graphql-scalars. Note that Scalars resolvers are generated in their schema module so.
• scalarsOverrides: Better implementation of externalResolvers + typesPluginsConfig.scalars.

In your case, since you are trying to override the Currency scalar, the config would look something like this:

import type { CodegenConfig } from "@graphql-codegen/cli";
import { defineConfig } from "@eddeee888/gcg-typescript-resolver-files";

const config: CodegenConfig = {
  schema: "**/schema.graphql",
  generates: {
    "src/schema": defineConfig({
      scalarsOverrides: {
        Currency: {
          resolver: "path/to/custom/scalars/Currency#Currency",
          type: "string", // Use this if you want to customise the Currency Scalar's  type 
        },
      },
    }),
  },
};
export default config;

[feychenie]

Thanks @eddeee888! I just implemented a couple of scalars with the "current" method above, and it works well and solves my problem for now 👍🏻 🎉 I will play around a bit to see if I can find a way to make this nicer.

Looking forward to testing 0.5!